Bendix Corp. denied yesterday that it plans to sell any Martin Marietta Corp. operations if it succeeds in its $1.5 billion bid to take over the Bethesda-based conglomerate.

The denial came a day after Bendix mailed a formal merger proposal to Martin Marietta that said the company was considering selling some of Martin Marietta's non-aerospace businesses. In addition to rockets, aircraft components and other aerospace products, Martin Marietta makes cement, aluminum, chemicals, and sand and gravel--enterprises that are suffering in the recession.

The merger proposal, filed with the Securities and Exchange Commission, said "the purchaser has analyzed the possibility of divesting one or more of the non-aerospace divisions of the company, but the purchaser has made no determination to pursue any such transaction and has no plan or proposal with respect thereto."

In the statement released yesterday, Bendix "reaffirmed . . . that it has no plans to divest any of Martin Marietta's operations following a merger of the two companies."

Meanwhile, the Southfield, Mich., firm filed notice of its merger proposal with the Federal Trade Commission and the Justice Department, the first step in getting it reviewed for possible antitrust violations. One of the two agencies will review the proposal; FTC officials reportedly are eager to conduct that review.

And Standard & Poor's, a credit rating agency, said yesterday that it plans to go over its ratings of both firms.

Martin Marietta directors are scheduled to meet Monday to decide what to do about the unsolicited $43-a-share offer that Bendix made Wednesday. The board is expected to oppose the offer.